Re: [PATCH 2/2] flexcan: Enable/Disable the CAN regulator in probe/remove

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 06/10/2013 09:05 PM, Fabio Estevam wrote:
> Hi Marc,
> 
> On Mon, Jun 10, 2013 at 2:02 PM, Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>> On 06/05/2013 09:27 PM, Fabio Estevam wrote:
>>> mx28evk has two CAN ports and they are controlled by the same GPIO.
>>>
>>> If can0 runs flexcan_chip_stop(), then the regulator will be disabled, which
>>> means that can1 cannot run anymore.
>>
>> Are you sure? I think the regulator framework has a proper refcount.
> 
> Yes, the refcount is OK. The problem is that on mx28evk we have two
> CAN ports controlled by the same regulator.
> 
> Let's say that can0 executes flexcan_chip_stop:
> 
> static void flexcan_chip_stop(struct net_device *dev)
> {
> 	struct flexcan_priv *priv = netdev_priv(dev);
> 	struct flexcan_regs __iomem *regs = priv->base;
> 	u32 reg;
> 
> 	/* Disable all interrupts */
> 	flexcan_write(0, &regs->imask1);
> 
> 	/* Disable + halt module */
> 	reg = flexcan_read(&regs->mcr);
> 	reg |= FLEXCAN_MCR_MDIS | FLEXCAN_MCR_HALT;
> 	flexcan_write(reg, &regs->mcr);
> 
>         if (priv->reg_xceiver)
> 	        regulator_disabled(priv->reg_xceiver);
> ...
> 
> It will turn off the transceiver here, which means that can1 will not
> be able to operate.
> 
> Currently this situation is properly handled inside mach-mxs by only
> disabling the CAN transceiver when both CAN ports are not used.

Why don't you enable the regulator in can1, too?

Marc

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